Python Training Knowledge Summary Series-chapter II Python data Structure Part II, string concatenation

Three methods of Python string connection and their efficiency and application scenarios
The Python string connection method, generally has the following three kinds: Method 1: Directly through the plus (+) operator connection website=& 39;python& 39;+& 39;tab& 39;+& 39; com& 39; Method 2

The Python string connection method, generally has the following three kinds:

Method 1: Connect directly via the plus (+) operator

1
Website = ' python ' + ' tab ' + '. com '
Method 2:join Method

1
2
Liststr = [' Python ', ' tab ', '. com ']
Website = ". Join (LISTSTR)
Method 3: Replace

1
Website = '%s%s%s '% (' python ', ' tab ', '. com ')

Let's take a look at the difference between the three ways.

Method 1, simple and straightforward to use, but many online people say this method is inefficient

The reason why Python uses + for string connections is inefficient because the strings in Python are immutable types, a new string is generated when using + to concatenate two strings, and a new string is required to re-request the memory, when the string of successive additions is many (a+b+c+d+ e+f+ ...) , inefficiency is inevitable.

Method 2 uses a slightly more complex, but high-efficiency connection to multiple characters, with only one memory request. And if the character of the list is connected, this method must be the preferred

Method 3: String formatting, this method is very common, I also recommend the use of this method

Python Training Knowledge Summary Series-chapter II Python data Structure Part II, string concatenation